Usefulness of duckbill‐type anti‐reflux self‐expandable metal stents for distal malignant biliary obstruction with duodenal invasion: A pilot study

Abstract

Objectives Early obstruction of a self‐expandable metal stent placed for distal malignant biliary obstruction is more likely to occur in the presence of duodenal invasion. An anti‐reflux self‐expandable metal stent (ARMS) has been developed for the purpose of preventing duodenal fluid reflux into the bile duct. In this study, we evaluated the usefulness and safety of a duckbill‐type ARMS (D‐ARMS) in the situation of duodenal invasion. Methods We retrospectively analyzed 10 consecutive patients who received D‐ARMS for distal malignant biliary obstruction with duodenal invasion. We evaluated non‐occlusion cholangitis, recurrent biliary obstruction (RBO), and adverse events after D‐ARMS placement. Results There were no cases of non‐occlusion cholangitis. RBO was observed in 2 patients (20%), and time to RBO was 236 days and 117 days, respectively. The causes of RBO were overgrowth and sludge formation. The median time to RBO was 382 days (range, 117–382 days). Only one adverse event was observed (cholecystitis). Conclusions D‐ARMS shows potential as an optimal ARMS.

The efficacy and safety of a duckbill‐type anti‐reflux metal stent as the initial metal stent for distal malignant biliary obstruction in unresectable pancreatic cancer

“…Since a previous in vitro study showed that a duodenal pH environment caused a morphological change of ARV, 27 the development of a new ARV that is not affected by the duodenal pH environment might be necessary to improve the durability of the ARV. Third, the rate of tumor ingrowth was high in this study (18%) compared to previous studies using DMS 12,13,15,28 . This could be explained by the difference in the proportion of SEMS‐naïve patients and the duration of the indwelling period of SEMS 29 .…”

“…Third, the rate of tumor ingrowth was high in this study (18%) compared to previous studies using DMS. 12 , 13 , 15 , 28 This could be explained by the difference in the proportion of SEMS‐naïve patients and the duration of the indwelling period of SEMS. 29 We speculated that the external force applied to the covered membrane of a laser‐cut type SEMS may become strong enough to cause tumor ingrowth, especially when used in SEMS‐naïve patients with a long indwelling time.…”

“…Duckbill‐type anti‐reflux metal stent (DMS) is a novel fully covered laser‐cut type ARMS. Several studies including ours have reported the efficacy and safety of this stent 12–16 and DMS was reported to be more effective than conventional CMS (c‐CMS) when used in the preoperative setting 12 or reinterventions after CMS dysfunction 15 . However, the superiority of DMS over c‐CMS when used as the initial SEMS for unresectable PC has not been elucidated.…”